Reconfigurable jet pump

ABSTRACT

The present invention provides reconfigurable jet pump that is also inexpensive to fabricate. In one preferred embodiment of the present invention, a jet pump is formed as a nozzle and a diffuser attached to a standard tube or pipe T-shape fitting. Suitable T-shape fittings may have one or more joints where seals is formed by a compression/deformation of certain elements. The subject invention fulfills and important need for a jet pump that can be produced inexpensively and can be reconfigured at conform to new operating condition without the need to replace the entire unit. This feature is very important in fluid installations such as chemical plants where the physical parameters of the fluid (such as density, viscosity, bubble content, etc.) or the operating flow conditions (pressures, flow rates) are not precisely known and experimentation may be required to achieve best performance of the jet pump.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from the U.S. provisional patent application U.S. Ser. No. 61/201,886, filed on Dec. 16, 2008, entitled “RECONFIGURABLE JET PUMP.”

GOVERNMENT RIGHTS IN THIS INVENTION

This invention was made with U.S. government support under contract number FA8650-08-M-5026. The U.S. government may have certain rights in this invention.

FIELD OF THE INVENTION

This invention relates generally to apparatus and methods for jet pumps and more specifically to jet pumps suitable for easy reconfiguration.

BACKGROUND OF THE INVENTION

The invention is for a jet pump apparatus and method. Jet pumps (also know as ejectors, eductors, or thermo-compressors) are used in industry for pumping of liquids and fluides, see for example, R. H. Perry and C. H. Chilton, “Chemical Engineer's Handbook,” 5^(th) edition, Chapter 6, Section “Ejectors,” pages 6-29 to 6-32, published by McGraw-Hill Book Company, New York, N.Y., 1973, and G. L. Weissler and R. W. Carlson (editors), “Vacuum Physics and Technology,” Chapter 4.3.5: Ejectors, pages 136 to 138, published by Academic Press, New York, N.Y., 1979. One key advantage of ejector pumps is that they are mechanically simple as they have no pistons, rotors, or other moving components. FIG. 1 shows a general configuration of a fluid (liquid, gas, or steam) operated ejector pump for pumping fluids. In this disclosure, the term “ejector pump” shall mean a -operated ejector pump. Ejector pump essentially consists of a fluid-operated driving nozzle, a suction chamber and a diffuser duct. The diffuser duct typically has two sections; a mixing section which may have converging and/or straight segments, and a pressure recovery section which is usually diverging. The driving nozzle is fed a high-pressure “driving” fluid (liquid, gas, or steam) at pressure p₁ and converts its potential (pressure) energy into a kinetic energy thereby producing a high-velocity fluid jet discharging into the suction chamber. Pumping action occurs when the fluid in the suction chamber is entrained by the jet, acquires some of its velocity, and is carried into the diffuser duct where the kinetic energy of the mixture of driving and entrained fluids is converted into a potential (pressure) energy. In particular, the velocity of the fluid mixture is recovered inside the diffuser to a pressure p₃ which is greater than the suction pressure p₂ but lower than the driving pressure p₁. For stable operation the diffuser exit pressure p₃ must be equal or higher than the backing pressure p₄. Ejector design is termed subsonic if the fluid velocity in the diffuser is subsonic. Conversely, ejector design is termed supersonic if the fluid velocity in the diffuser is supersonic. Hence, a supersonic ejector requires that the driving nozzle is a supersonic nozzle. Typically, diffuser ducts used in ejector pumps have a circular cross-section because it provides the largest cross-sectional area with the least circumference and, therefore, the least wall friction losses.

In practice, ejector pumps have been used to produce compression ratio P₃/p₂ of up to about 10. To achieve high compression ratio p₃/p₂ it is necessary that the driving fluid pressure p₁ is much higher than the target pressure p₃ at the exit of the ejector, i.e., p₁>>p₃. Consequently, ejector pumps can be used as vacuum pumps or as compressors. Ejector pumps can be designed to accommodate a wide variety of flow conditions. As a results, ejector pumps for different applications can greatly vary in size, nozzle and duct shape, and arrangement of components. The ejector configuration having a centrally located driving nozzle immersed in the inlet fluid flow shown in FIG. 1 is known as the in-line ejector. FIG. 2 shows an alternative configuration known as the annular jet ejector where the driving nozzle is formed as an annulus enveloping the inlet fluid flow. Data on commercially produced fluid ejector pumps and their performance can be found, for example, in “Pumping Gases, Jet Pump Technical Data,” Section 1000, Bulletin 1300, Issued March 1976 by Penberthy Division of Houdaille Industries, Inc., Prophetstown, Ill.

In an ejector with fixed geometry, flow throughput and pressure of driving fluid can be varied to produce desired discharge port pressure p₃ over a broad range of pumped fluid inflows and pressures p₂. To increase ejector pump throughput beyond the capacity of a single ejector, several ejector pumps can be operated in parallel. Alternately, multiple driving nozzles can be used to feed a single large cross-section diffuser duct (see, for example FIG. 6-71 in the above noted Perry and Chilton).

Prior art jet pumps are made with a suction chamber and diffuser formed as one piece typically produced by casting, molding, and/or machining. This results in a costly product. In addition, the configuration of the diffuser (which affects jet pump performance) is thereby fixed and unchangeable. FIGS. 3 and 4 show examples of prior art jet pumps. There is a need for a jet pump that can be produced inexpensively and can be reconfigured at conform to new operating conditions.

In summary, prior art does not teach a capable of fast response that is also simple, lightweight, compact, and inexpensive to fabricate. It is against this background that the significant improvements and advancements of the present invention have taken place.

SUMMARY OF THE INVENTION

The present invention provides a reconfigurable jet pump that is also inexpensive to fabricate. In one preferred embodiment of the present invention, a reconfigurable jet pump is formed as a nozzle element and a diffuser element each being attached in in-line arrangement to a standard tube T-shape fitting or a standard pipe T-shape fitting. T-shape fittings are inexpensive commercial off-the-shelf items used in tube or pipe systems. In particular, there are T-shape fittings for tubes that use one or more joints where seals is formed by a compression/deformation of certain elements. Some classes of such fittings are known as Swagelok fittings and UltraTorr fittings respectively, each of which can be obtained from Swagelok Inc., Solon, Ohio. In a T-type compression fitting there is a first in-line port, a second in-line port, and a side port, see FIGS. 5 and 6. It is important to note, that the compression type fitting such as above mentioned the Swagelok and Ultra Torr type fittings automatically axially align the tubes (or other components with appropriate outside diameter) installed in the in-line ports to a great degree of accuracy. This feature is important to the subject invention. The subject invention fulfills and important need for a jet pump that can be produced inexpensively and can be reconfigured to conform to new operating conditions. This feature is very important in fluid installations such as chemical plants where the physical parameters of the fluid (such as density, viscosity, bubble content, etc.) or the operating flow conditions (pressures, flow rates) are not precisely known and experimentation may be required to achieve best performance of the jet pump.

Accordingly, it is an object of the present invention to provide a reconfigurable jet pump that is also and inexpensive to fabricate.

These and other objects of the present invention will become apparent upon a reading of the following specification and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a general configuration of a jet pump (Prior Art).

FIG. 2 shows a general configuration of a jet pump (Prior Art).

FIG. 3 shows a prior art jet pump.

FIG. 4 shows another prior art jet pump.

FIG. 5 shows a Swagelok T-style fitting with 3 compression ports

FIG. 6 shows another Swagelok T-style fitting with 2 compression ports

FIG. 7 is a cross-sectional view of the reconfigurable jet pump of the subject invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Selected embodiments of the present invention will now be explained with reference to drawings. In the drawings, identical components are provided with identical reference symbols. It will be apparent to those skilled in the art from this disclosure that the following descriptions of the embodiments of the present invention are merely exemplary in nature and are in no way intended to limit the invention, its application, or uses.

Referring now to FIG. 7, there is shown a cross-sectional view through a jet pump 100. The jet pump 100 comprises a fitting body 102, a nozzle. element 104, and a diffuser element 106. The fitting body 102 is preferably a T-shape tube fitting having a first compression type port 108 and a second compression port 110, with the two ports being arranged in-line. Compression style ports typically comprise a hollow threaded nut 109 and a mating thread 111 on the fitting body 102. As already noted, this type of fitting allows for precise axial alignment of the nozzle element 104 and the diffuser element 106, which is important to the subject invention. Connection style of the side port 112 may be a compression type, pipe thread, or other suitable connection, and it may be formed as either male or female. The nozzle element 104 is attached to the body 102 via a first in-line compression port 108 and made to be substantially mechanically rigid and substantially sealing for the working fluid. Suitable mechanical rigidity and fluid seal may be accomplished, for example, by appropriately tightening the hollow nut 109. The diffuser element 106 is attached to the body 102 via the second in-line compression port 110 and made to be substantially mechanically rigid and substantially sealing for the working fluid. Suitable mechanical rigidity and fluid seal may be accomplished, for example, by appropriately tightening the hollow nut 109.

The nozzle element 104 may be formed as a substantially cylindrical body 116 having an internal passage 118, a driving nozzle 114 formed on the end of the cylindrical body 116 being inserted into the first inlet 108, and a suitable fluid connection style on the end of the cylindrical body 116 being outside the fitting body 102. The diffuser element 106 may be formed as a substantially cylindrical body 126 having an internal diffuser duct 128. into the second port 102 and a suitable fluid connection style on the cylindrical body end outside the fitting body 102. The diffuser duct 128 may have a rounded or conical inlet 124 on the end inserted into the second compression type port 110 and have a diverging portion 132 on the opposite end. The nozzle element 104 and the diffuser element 106 are axially positioned in their respective ports 108 and 110 so that the space between the driving nozzle 114 and the inlet 124 form a suction chamber 142 fluidly connected to the inlet 134 of the side port 112.

In operation, the nozzle element is connected to a source of suitable driving (motive) fluid 120 (liquid, gas, or steam) provided at a high pressure and the side port is connected to a source of suitable inlet fluid 130 (liquid, gas, or vapor) provided at a lower pressure. The motive fluid 120 is injected into the suction chamber 142 via the driving nozzle 114, mixes with and entrains a portion of the inlet fluid 130, and forces the mixture into the diffuser passage 128. Velocity of mixed fluid 140 is converted in-part into pressure and the fluid is discharged into a suitable fluid duct, chamber, or open space.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” and “includes” and/or “including” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. For example, these terms can be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.

Moreover, terms that are expressed as “means-plus function” in the claims should include any structure that can be utilized to carry out the function of that part of the present invention. In addition, the term “configured” as used herein to describe a component, section or part of a device includes hardware and/or software that is constructed and/or programmed to carry out the desired function.

While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the present invention as defined in the appended claims. Furthermore, the foregoing description of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the present invention as defined by the appended claims and their equivalents. Thus, the scope of the present invention is not limited to the disclosed embodiments. 

1. A jet pump apparatus comprising: a) A “T”-style fluid fitting having a first in-line compression type port, a second in-line compression type port, and a side port; b) a nozzle element installed in said first in-line compression type port; and c) a diffuser element installed in said second in-line compression type port.
 2. The jet pump apparatus of claim 1 wherein said “T”-style fluid fitting is a tube fitting.
 3. The jet pump apparatus of claim 1 wherein said “T”-style fluid fitting is selected from a group consisting of a Swagelok-type fitting and an Ultra Torr-type fitting.
 4. The jet pump apparatus of claim 1 wherein said nozzle element further comprises a driving nozzle.
 5. The jet pump apparatus of claim 1 further comprising a suction chamber. 